The present invention relates to a masking apparatus and a method of fabricating an electronic component, and particularly relates to a masking technique for forming an external structural body, such as a terminal electrode, on an outer peripheral surface of a chip-type electronic component.
Various electronic components are available today, such as: various discrete components including chip capacitors, chip inductors and chip resistors; and various electronic devices in each of which a plurality of active and/or passive elements are combined. Any of these electronic components needs terminal electrodes for establishing an electrical and mechanical connection with the outside so as to be mounted on a wiring board.
Such a terminal electrode can be formed by firstly forming a base electrode by a vapor deposition method such as sputtering, and by then plating a main conductor layer, which will serve as a main layer of the electrode, on the base electrode. For forming the base electrode, a masking apparatus is used in order to selectively form films on surfaces, on which electrodes are to be formed, of a component. This masking apparatus generally includes a mask base body and a mask plate. The mask base body holds individual chip-type electronic components obtained by dicing, while the mask plate includes a film-forming opening formed therein and corresponding to the shape of an electrode to be formed. A chip-type electronic component (hereinafter, sometimes referred to simply as a chip) is housed in a cavity of the mask base body in a state where a surface, to be processed, of the chip faces up. Then, the mask plate is placed on the top of the cavity (the mask base body), and a film-forming process is then carried out.
Not only a vapor deposition method, but also other film-forming methods, such as a paste printing method in which a conductive paste is applied, an ink jet method, and a transfer method, are widely used for forming such electrodes.
What is formed on an outer surface of a chip is not limited to the terminal electrode for external connection, and various film-shaped structures (external structural bodies) are also formed thereon. Such film-shaped structures include a connection pad used for mounting another element on the chip, wiring arranged on the outer surface of the chip. Moreover, the film-shaped structures to be formed thereon also include an insulating film that is selectively disposed for forming wiring on the outer surface of the conductive chip of a semiconductor or a metallic plate.
A masking apparatus is disclosed, for instance, in Japanese Patent Unexamined Application Publication No. Hei 4-13858.